Older women don't need mammograms every year

For older women, having a mammogram every two years to look for breast cancer is as beneficial as getting screened annually, reports a new study.

Researchers at the University of California, San Francisco found that screening women between the ages of 66 and 74 every other year instead of every year does not increase the likelihood that the women will be diagnosed with late-stage breast cancer.

What's more, biennial mammography screening leads to fewer false-positive results in these women. The researchers found that 48 percent of women between the ages 66 and 74 who underwent annual mammograms had false-positive results. Just 29 percent of women in that age group who were screened every two years had such results.

A false-positive result occurs when the radiologist detects a suspicious lesion in the breast that isn’t malignant. But follow-up testing, such as ultrasound or a biopsy, must be done to rule out cancer.

Having other illnesses such as diabetes or heart disease did not affect the ratio of benefit to harm in screening older women, according to the researchers.

For this study, scientists analyzed screening data for 2,993 women between the ages of 66 and 89 who had been diagnosed with breast cancer, and 137,949 women in the same age group who didn't have breast cancer.

The U.S. Preventive Services Task Force recommends that women ages 50 to 74 get a mammogram every two years, noting that "the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older." The American Cancer Society recommends that women 40 and older have a mammogram every year starting at age 40 and continuing as long as they are in good health.

The study "fills an important information gap, since accountable care organizations do not address screening intervals or screening cessation in women of advanced age or with a significant burden of illness," study co-author Dejana Braithwaite, Ph.D., said in a statement.

Older women who have mammograms every two years can now breathe a little easier. "They get no added benefit from annual screening, and face almost twice the false-positives and biopsy recommendations, which may cause anxiety and inconvenience," senior study author Karla Kerlikowske, M.D., said in a statement.

The study appears online Feb. 5 in the Journal of the National Cancer Institute.